Nonlinear Analysis of Interaction of Superstructure-Pile-Raft-Soil System in Layered Soil — Part II: Characteristics of Reaction Force on Pile Head and Displacement of Raft

2008 ◽  
Vol 400-402 ◽  
pp. 659-666
Author(s):  
Jun Chen ◽  
Yong Hong Chang ◽  
Yin Sheng Zou
Keyword(s):  
Nonlinear Analysis ◽  
Quantitative Data ◽  
Reaction Force ◽  
The State ◽  
Layered Soil ◽  
Analysis Method ◽  
Pile Head ◽  
Soil System ◽  
Piled Raft ◽  
Piled Raft Foundation

Using the nonlinear analysis method and program of the interaction of superstructure- pile-raft-soil system in layered soil in the state of the previous literature, the reaction force on the pile head and the displacement characteristics of raft of the piled-raft foundation are analysed when the thickness of the raft, the spacing of the piles, the length and the diameter of the pile are changed. Some quantitative data and qualitative conclusions are obtained in this paper.

Simplified assessment of pile-head kinematic demand in layered soil

2020 ◽  
Vol 130 ◽  
pp. 105975 ◽  
Author(s):  
Stefano Stacul ◽  
Nunziante Squeglia
Keyword(s):  
Layered Soil ◽  
Pile Head

scholarly journals Vertical Vibration Characteristics of a Variable Impedance Pile Embedded in Layered Soil

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Wenbing Wu ◽  
Xuelian Xu ◽  
Hao Liu ◽  
Changliang Fang ◽  
Bin Dou ◽  
...  
Keyword(s):  
Variable Cross Section ◽  
Efficient Solutions ◽  
Vertical Vibration ◽  
Vibration Characteristics ◽  
Layered Soil ◽  
Variable Cross ◽  
Pile Head ◽  
Transform Method ◽  
Soil System ◽  
Velocity Response

In engineering applications, various defects such as bulging, necking, slurry crappy, and weak concrete are always observed during pile integrity testing. To provide more reasonable basis for assessing the above defects, this paper proposed simple and computationally efficient solutions to investigate the vertical vibration characteristics of a variable impedance pile embedded in layered soil. The governing equations of pile-soil system undergoing a vertical dynamic loading are built based on the plane strain model and fictitious soil pile model. By employing the Laplace transform method and impedance function transfer method, the analytical solution of the velocity response at the pile head is derived in the frequency domain. Then, the corresponding semianalytical solution in the time domain for the velocity response of a pile subjected to a semisinusoidal force applied at the pile head is obtained by adopting inverse Fourier transform and convolution theorem. Based on the presented solutions, a parametric study is conducted to study the vertical vibration characteristics of variable cross-section pile and variable modulus pile. The study gives an important insight into the evaluation of the construction quality of pile.

Pile-head kinematic bending in layered soil

2012 ◽  
Vol 42 (3) ◽  
pp. 319-337 ◽  
Author(s):  
Raffaele Di Laora ◽  
George Mylonakis ◽  
Alessandro Mandolini
Keyword(s):  
Layered Soil ◽  
Pile Head

Nonlinear Analysis of Interaction of Superstructure-Pile-Raft-Soil System in Layered Soil — Part I: Formulation of Interaction Equation

2008 ◽  
Vol 400-402 ◽  
pp. 651-658 ◽  
Author(s):  
Jun Chen ◽  
Yong Hong Chang ◽  
Yin Sheng Zou
Keyword(s):  
Stiffness Matrix ◽  
Reaction Force ◽  
Interaction Mechanism ◽  
Layered Soil ◽  
Pile Head ◽  
Displacement Method ◽  
Soil System ◽  
Piled Raft Foundation ◽  
Shear Displacement Method ◽  
Interaction Equation

The layered soil model is used to simulate the nonlinear performances of the layered soil in this paper. Using the shear-displacement method, the flexibility coefficients of the pile-pile and the pile-soil are deduced based on the interaction mechanism of the pile-pile and the pile-soil in the layered soil. After that, the stiffness matrix of the pile-soil system can be established. Using coupling method presented in this paper, the interaction equation of superstructure-pile-raft-soil system is formulated. The interaction equations are used to analyze the reaction force on the pile head and the displacement characteristics of the raft of the piled-raft foundation in the layered soil and its practicality is excellent.

Prediction, Testing, and Analysis of a 50 m Long Pile in Soft Marine Clay

2019 ◽  
Vol 13 (2) ◽  
Author(s):  
Bengt Fellenius
Keyword(s):  
Peak Load ◽  
Pile Head ◽  
Marine Clay ◽  
Loading Test ◽  
Head Displacement ◽  
Floating Pile ◽  
Peak Loads ◽  
Static Loading Test ◽  
Beta Coefficient ◽  
Load Movement

On April 4, 2018, 209 days after driving, a static loading test was performed on a 50 m long, strain-gage instrumented, square 275-mm diameter, precast, shaft-bearing (“floating”) pile in Göteborg, Sweden. The soil profile consisted of a 90 m thick, soft, postglacial, marine clay. The groundwater table was at about 1.0 m depth. The undrained shear strength was about 20 kPa at 10 m depth and increased linearly to about 80 kPa at 55m depth. The load-distribution at the peak load correlated to an average effective stress beta-coefficient of 0.19 along the pile or, alternatively, a unit shaft shear resistance of 15 kPa at 10 m depth increasing to about 65 kPa at 50 m depth, indicating an α-coefficient of about 0.80. Prior to the test, geotechnical engineers around the world were invited to predict the load-movement curve to be established in the test—22 predictions from 10 countries were received. The predictions of pile stiffness, and pile head displacement showed considerable scatter, however. Predicted peak loads ranged from 65% to 200% of the actual 1,800-kN peak-load, and 35% to 300% of the load at 22-mm movement.

Comparison of the Bidirectional Load Test with the Top-Down Load Test

2005 ◽  
Vol 1936 (1) ◽  
pp. 108-116 ◽  
Author(s):  
Oh Sung Kwon ◽  
Yongkyu Choi ◽  
Ohkyun Kwon ◽  
Myoung Mo Kim
Keyword(s):  
Load Transfer ◽  
Measurement Data ◽  
Load Test ◽  
Load Testing ◽  
Pile Head ◽  
Top Down ◽  
Simple Method ◽  
Testing Method ◽  
Settlement Behavior ◽  
Cell Test

For the past decade, the Osterberg testing method (O-cell test) has been proved advantageous over the conventional pile load testing method in many aspects. However, because the O-cell test uses a loading mechanism entirely different from that of the conventional pile loading testing method, many investigators and practicing engineers have been concerned that the O-cell test would give inaccurate results, especially about the pile head settlement behavior. Therefore, a bidirectional load test using the Osterberg method and the conventional top-down load test were executed on 1.5-m diameter cast-in-place concrete piles at the same time and site. Strain gauges were placed on the piles. The two tests gave similar load transfer curves at various depth of piles. However, the top-down equivalent curve constructed from the bidirectional load test results predicted the pile head settlement under the pile design load to be approximately one half of that predicted by the conventional top-down load test. To improve the prediction accuracy of the top-down equivalent curve, a simple method that accounts for the pile compression was proposed. It was also shown that the strain gauge measurement data from the bidirectional load test could reproduce almost the same top-down curve.

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